Unilateral flank radiation a viable substitute to WAPRT for Wilms tumour

Children with Wilms tumour (WT) treated with abdominal radiation therapy (RT) may opt to receive unilateral flank radiation instead of whole abdominal and pelvic RT (WAPRT) for contained rupture or spillage, suggests a study.

This single institution retrospective study included 54 children (median age 4.5 years) with WT treated with abdominal RT between May 2000 and October 2022.

The authors determined the rate of local failure (LF) after abdominal RT, with a focus on patients with contained rupture treated with WAPRT or flank RT. They also estimated the OS, distant failure (DF), and late toxicities. Both LF and DF were calculated using cumulative incidence function, while OS was estimated using the Kaplan-Meier method.

Over a median follow-up of 6 years, 91 percent of patients achieved favourable histology, while only one had LF 15 months from RT completion (cumulative incidence, 2 percent at 5 years). Thirteen patients who received unilateral flank radiation for contained rupture/spillage achieved long-lasting intra-abdominal tumour control.

On the other hand, five children had a DF in the lung at a median of 7 months. None of the patients relapsed in the lungs following upfront whole lung irradiation (n=16). Five-year OS was 96 percent.

Additionally, hormonal irregularities or infertility occurred in four female patients with prior WAPRT out of 28 who were followed through puberty.

“Unilateral flank radiation may be a viable alternative to WAPRT for contained rupture/spillage and should be further explored prospectively,” the authors said. “Our results may also be utilized in the future for outcome and toxicity comparison as conformal radiation techniques evolve.”